The coding of the approximation sequence is recursive. DrRacket diagram

Question

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I am trying to solve this sequence:

I do this in a loop do, a stop-expression condition

But my loop is donot working. I can not find the error. Please help me. My code is:

(define (y a n x )
  (if (= n 0)
  a
  (* 0.5 (+ (y a (- n 1) x) (/ x (y a (- n 1) x))))
  )
  )
(define (f a x e)

 (do
  ( (n 0 (+ n 1)) )  


( ( < (abs (- (sqr (y a n x)) (sqr (y a (- n 1) x)))) e) ("end of loop")) 

(display (y a n x))
(newline)

)
 )

Answer 1

Indentation is your friend, not your enemy:

(define (y a n x)
  (if (= n 0)
    a
    (* 0.5 (+      (y a (- n 1) x) 
              (/ x (y a (- n 1) x)) )) ))

(define (f a x e)    
  (do ( (n 0 (+ n 1)) )  
      ( (< (abs (- (sqr (y a    n    x)) 
                   (sqr (y a (- n 1) x)) ))
           e) 
        ("end of loop")) 
    (display (y a n x))
    (newline)))

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3 2 1 0
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